As optical systems continue to increase the volume and speed of information communicated, the need for methods and apparatus operable to facilitate high speed optical signal processing also escalates. Router and switch cores performing optical switching generally implement schedulers to assist in avoiding contention for common system resources. In prior approaches, there has generally been a tension between the complexity of the scheduler used and the delay experienced in the switching fabric. More complex schedulers generally require significant system resources and can be difficult to implement. Trivial schedulers, while simple to implement, have generally resulted in unsatisfactory switching delays.
Overview of Various Example Embodiments
The present invention recognizes a need for a method and apparatus operable to efficiently and effectively facilitate scheduling of communication through a star switching fabric. In one embodiment, a scheduler for use with a star switching fabric comprises a scheduling star switching fabric operable to receive a plurality of packets each associated with one of a plurality of wavelengths, and a plurality of selecting elements associated with the scheduling star switching fabric. Each of the plurality of selecting elements is operable to contribute to selectively passing packets from the scheduling star switching fabric for receipt by a transmission star switching fabric. Packets received at the transmission star switching fabric over a given time period comprise a more uniform load distribution than packets received at an input to the scheduler over the same period of time.
In a method embodiment, a method of scheduling operation of a star switching fabric comprises receiving at a scheduler a plurality of packets each having a wavelength and communicating from a scheduling star switching fabric of the scheduler a plurality of substantially similar sets of the plurality of packets. The method further comprises selectively passing packets having selected wavelengths from the scheduling star switching fabric for receipt by a transmission star switching fabric. Packets received at the transmission star switching fabric over a given time period comprise a more uniform load distribution than packets received at an input to the scheduler over the same time period.
Depending on the specific features implemented, particular embodiments may exhibit some, none, or all of the following technical advantages. One embodiment provides a way to schedule communication of optical signals through a star switching fabric using a simple scheduling algorithm while maintaining good throughput. Other technical advantages are readily apparent to one of skill in the art from the attached figures, description, and claims.